Cillelas was a Noldorin Elf, son of an Elven Lord, and one among the survivor of the Destruction of Eregion. He was born in the First Age, after the kinslaying, and fled to Middle Earth where they ended up in Nargothrond. It was in that place where Cillelas spent most of his childhood, training in the art of the sword.

His family served the line of Feanor for a long time, and then moved out to Eregion when Cillelas was at his young adulthood. In Eregion, where they served Celebrimbor, Cillelas learned many secrets and the arts of crafting.. As he reached his adulthood, he was wed with and Elven lady in Eregion.

When Sauron attacked Eregion, laying waste to the realm, Cillelas and his family fled to Gil-Galad's kingdom: Lindon, hearing the news that Celebrimbor was lost, Cillelas family served Gil-Galad's House, and with his unquestioned loyalty, he remained at the King's side until the War of the Last Alliance.

It is on the plain of Dagorlad where Lord Cillelas, advisor to King Gil-Galad and a leader of an Elven Noldor regiment, met with Prince-in-Exiled Adanaethor Elthoron. Despite by the hostility between the Noldor and the Silvan, Cillelas and Adanaethor fought together.

As the War ended, and both Elendil and Gil-Galad slained, Cillelas returned to Lindon, where on the other hand Adanaethor returned to Greenwood.

He arrived in Lindon, with the remnants of the Noldor regiments, and found his family gone to the South, seeking refuge in Imladris, under the protection of Elrond.

Days passed as Cillelas' heart became cold. There was little joy in him and he became very solemn. After he found himself doing nothing in Lindon, he moved out to Central Eriador, where he met his old friend Adanaethor Elthoron.

He joins Adanaethor's clan, The Wardens of Aman, since he felt that its cause is just. Until now, Cillelas became a great friend to Adanaethor, and he is one of the Elves with royal blood who joins the Wardens.